Forum » Practical Standalone Tuning » Semi sequential injection

Semi sequential injection

Practical Standalone Tuning

Forum Posts



Tech Articles

Discussion and questions related to the course Practical Standalone Tuning

= Resolved threads

Page 1


I'm building a VW vr6 turbo and looking at the link Monsoon ECU.

I'm think about using semi sequential injection to fire multiple injectors. Can I have two lots of two injects wired together and have two fire single injectors.

The reason I ask is , I will probably need more fuel on the hots side .

Not something I've had much (or any IIRC) but there are at least two different versions of the engine, and they seem to use offset crankpins to compensate for the narrow angle "V" to gain an even firing interval. If that's correct, you can batch fire each pair that come up to TDC, providing ~half the fuel for each - however, because of the head design there's quite a significant inlet runner length variation that "may" affect the ultimate fuelling requirements for each pair of cylinders. If it's not correct, you may need to play around to get the best injection timing

Not sure what the reason means?

Is there any particular reason you can't just use a single injector per cylinder, correctly sized and running fuel pressure within their operating range? That may also allow any fuel trimming between banks should it be required.

With semi-sequential you wire injectors from adjacent cylinders together (adjacent in terms of firing order), so in terms of a 6cyl engine one of the cylinders of the pair would get injector timing 60deg earlier than ideal and 1 would get injector timing 60deg later than ideal. Since the injectors are wired in pairs, you can only trim the pair of cylinders - So if your "hot cylinders" happened to be one of these pairs it will work, otherwise no. On the VR6 the pairs would be cyls 1&5, 3&6 and 2&4.

Otherwise for proper individual cylinder control you will need to move up to an ECU with enough injector drives to do full sequential.